USB Question: unable to open /dev/ugen0 more than once

Michael E. Mercer mmercer at nc.rr.com
Thu Nov 20 11:38:34 PST 2003


Hello peoples,

Question: Should I be able to open /dev/ugen0 more than once?

I am using FreeBSD 4.9-Stable, libusb-0.1.7.
>From reading the libusb docs, you must open the device for each
interface you want to acquire. However, once it is opened once, it can't
be opened again. 

Furthermore, calls to usb_find_devices() shows that /dev/ugen0 has
disappeared. Investigation on how they(libusb) finds devices, shows they
are trying to open the device read only... this is where it tries to
open it the second time. This second try fails and therefore libusb
thinks the device was removed.

Question: Is this the correct behavior?

Any help/insight would be greatly appreciated.

Michael E Mercer 



More information about the freebsd-questions mailing list